Semiautomatic firearms have been in use for over a century, and are popular for military, law enforcement, defensive, and sporting purposes. A semiautomatic firearm utilizes a reciprocating bolt or slide. Retraction of the slide upon discharging the weapon ejects the spent casing from the chamber. The slide then returns forward under spring pressure, carrying a fresh cartridge from the magazine into the chamber. The frame of a semiautomatic handgun typically includes an ejector for pushing the spent casing out of an ejection port in a predetermined direction. The slide typically includes a spring biased extractor having a hook for engaging the rim of a casing, permitting the casing to be extracted from the chamber in the absence of discharging a firearm.
It is necessary to control the retraction of the slide so that the slide does not retract a significant distance before the bullet exits the muzzle. While the bullet is being propelled forward within the barrel, gas pressure within the barrel is quite high. Excessive retraction of the slide at this time would direct at least some of this high gas pressure in undesirable directions, potentially endangering the shooter. Various mechanisms have been developed toward this end.
The simplest method of controlling slide retraction, commonly known as straight blowback, simply relies on gas pressure inside the casing to retract the slide. The mass of the slide, as well as the strength of the recoil spring, are selected so that the slide does not travel rearward a significant distance before the bullet exits the muzzle. This system is commonly used with small caliber semiautomatic handguns, up to and including 0.380 ACP. Because the barrel of such handguns is fixed, some handguns utilizing the system utilize a recoil spring that is coiled around the barrel, so that the barrel effectively serves as a recoil spring guide. Due to the increasing slide mass and recoil spring strength required with increasing pressure levels, this system is typically not utilized for handguns of 9×19 mm. caliber or higher calibers.
With increasing pressure levels, other mechanisms are necessary to ensure that significant slide retraction does not occur before the bullet leaves the muzzle, ensuring that gas pressure within the barrel has dropped to a safe level. A tilting barrel system is commonly used for this purpose. In such systems, the barrel is locked to the slide by either a projection that fits within the ejection port of the slide, or by a plurality of locking lugs that engage corresponding locking lugs on the interior of the slide. As the slide retracts, the barrel moves rearward with the slide for a short distance, before a pivoting link or lug on the bottom of the barrel causes the breech end of the barrel to pivot downward, disengaging with the slide, and allowing the slide to continue to retract independently. All such systems which are known to be present inventors utilize a recoil spring assembly that is adjacent to the barrel, thereby occupying additional space that could otherwise be occupied by additional devices.
Another means of ensuring that the barrel and slide do not disengage prematurely is a gas retarded blowback system, such as that used within the Heckler & Koch P7 pistol. This system is similar to a straight blowback design, but utilizes a vent within the barrel to direct gas into a cylinder that contains a piston. When the pistol is discharged, the piston applies forward pressure to the slide until the bullet exits the muzzle, thereby resisting premature slide retraction. This mechanism results in reduced felt recoil, contributing to the accuracy with which the firearm may be shot. This mechanism also permits the recoil spring to be coiled around the barrel. However, this system is difficult to manufacture, and can in some instances result in excessive heat buildup within the firearm.
Other systems for controlling the movement of the slide include the falling locking block design of the Beretta 92F pistol, which provides for in-line movement of the barrel. This in-line barrel movement enhances the accuracy of the pistol. However, the locking block is subject to wear. The recoil spring of this pistol is located underneath the barrel, thereby adding bulk to the overall design.
Accordingly, there is a need for a system that controls the movement of the slide with respect to the barrel, wherein the recoil spring is coiled around the barrel, and avoiding the disadvantages of gas retarded blowback designs. Such a system would reduce the weight and bulk of the firearm, particularly when lights, laser aiming devices, or other accessories are secured to the dust cover of the frame, located in front of the trigger guard and below the barrel.
Sighting systems for handguns generally fall within two types. Iron sights typically consist of a post adjacent to the muzzle, which is aligned with a rear sight in the form of a U-shaped notch, V-shaped groove, or aperture. Iron sights may in some instances include various features to improve visibility, such as coloring, dots, fiber optic inserts, and/or tritium inserts. Iron sights are simple, generally durable, and compact. However, they often provide no indication of the proper lead for hitting a moving target.
Optical sighting systems, such as those using illuminated dot reticles, display an illuminated dot or other shape that is placed over the target when looking through the sight. Some optical sights provide a means of estimating lead for hitting moving targets. However, such sights add bulk and weight to a firearm. Particularly in the case of a handgun, such sights can increase the difficulty of carrying the handgun, particularly if concealment is important. Furthermore, such sights are often dependent upon batteries or other illumination means such as tritium. In the case of iron sights, if the tritium inserts go dim, the iron sights themselves are still useful. However, in the event of a battery powered or tritium powered optical sight, if the battery dies or the tritium goes dim, the sight is significantly less useful.
Accordingly, there is a need for a sighting system that combines the simplicity, ruggedness, and compactness of iron sights with a means of estimating lead when shooting at a moving target. Moving targets are common in both sporting and practical shooting applications, making a means of lead estimation particularly useful.
Many shooting situations in both sporting and practical contexts require the ability to manipulate the firearm with only one hand, including not only aiming and trigger squeeze, but also reloading and malfunction clearance. Reloading and clearing a malfunction require the ability to manipulate the slide. When working with only one hand, for example, in the case of a real or simulated injury, a portion of the slide such as the rear sight, ejection port, or muzzle portion of the slide is generally engaged with the shooters belt, the heal of the shooters shoe, or a convenient nearby hard surface.
However, many presently available handguns do not include a convenient projection on the slide for use during one-handed slide retraction. While some rear sights include a vertical forward surface that is useful for engaging convenient objects to retract the slide, many popular rear sights include a sloped forward surface, making the rear sight difficult to hook. Furthermore, although some ejection ports, such as those on a 1911 handgun, are easy to engage, ejection ports that lock up with the barrel by receiving a portion of the barrel have little excess material for engaging convenient objects to retract the slide. Many handguns are not suited for slide retraction by pushing the muzzle end of the slide against a convenient object, and this method of slide retraction is typically only practiced with full-size 1911 handguns without full-length guide rods. While it is known to include an additional projection within the slide to aid in one hand manipulation, the very few presently available projections would limit the selection of compatible sights, as well as interfere with some older methods of malfunction clearance, such as wiping the hand across the top of the slide to clear a stovepipe malfunction.
Some users attempt to overcome the above-described deficiency by applying skateboard tape to the top of the slide. The application of skateboard tape results in cosmetic disadvantages, as well as the potential for the tape to wear or to lose adhesion.
Accordingly, there is a need for a handgun slide having a means of engaging a convenient surface to facilitate one-handed slide retraction without interfering with the selection of sights or with the user's preferred method of malfunction clearance.
Presently available semiautomatic handguns utilize a detachable box magazine that is held in place in one of two ways. The most common method is a catch engaging a hole defined within the body of the magazine. The catch is released utilizing a button that is reciprocally secured within the frame of the handgun, behind and slightly below the trigger guard, for actuation with the user's thumb. The design of the magazine release must balance the ease with which the magazine can be released intentionally with the need to avoid releasing the magazine unintentionally. These needs are typically balanced by the size of the magazine release button, the strength of the magazine release spring, and/or the placement of the magazine release button. Often, the magazine release button is placed so that slight rotation of the handgun within the user's hand is required to engage the magazine release with the shooter's thumb and release the magazine. Although this location minimizes the likelihood of accidental magazine release, it also slows the speed of reloading. Other presently available handguns utilize a magazine catch located at the base of the grip, sitting underneath the bottom of the magazine. Although this style of magazine catch is generally more secure, it is much slower to reload, and can make malfunction clearance significantly more difficult.
In the field of semiautomatic rifles, it is known to automatically eject a stripper clip from an M1 Garand rifle upon firing the last round within the magazine. However, the present inventors are unaware of any prior means of automatically releasing a box magazine from a semiautomatic firearm upon firing the last round within the magazine. Such a feature would significantly speed reloading not only by avoiding the need to depress the magazine release, but also by avoiding the need to shift the user's grip. The user would simply be able to focus on grasping and inserting the fresh magazine, and chambering the next cartridge.
Shooters involved in stressful situations, whether competition or life and death struggles, have been known to lose count of the number of cartridges remaining within their magazine. With most semiautomatic firearms, determining the number of cartridges remaining in a magazine requires removal of the magazine, which may be undesirable depending on the anticipated immediacy with which the firearm may be needed. At least one semiautomatic handgun, known as the ASP, attempted to address this need with transparent grip panels, permitting the shooter to determine the number of cartridges remaining by looking at the side of the pistol. However, in poor light conditions, determining the number of cartridges remaining is still potentially difficult. Accordingly, a means of determining the number of cartridges remaining within a magazine, even in poor light, is desired.